The LightSail spacecraft has completed the primary objective of its first test flight: unfurling its solar sail. The vehicle took a picture of itself, showing the sail stretched out over a span of 344 square feet as the spacecraft soared in low-Earth orbit.
LightSail is designed to harness the power of sunlight in the same manner that a sailboat captures the wind to carry it across the water. To do this, the vehicle utilizes a Mylar sail capable of harnessing the momentum of photons of light racing from the sun. Although these light-carrying packets would have zero mass if they were to ever come to rest, their velocity provides photons with momentum, which can help drive spacecraft around the inner solar system. Just like sailboats on the Earth, these vehicles are capable of riding with the breeze or tacking sails to head into the wind.
The Planetary Society designed and manages the vehicle, which launched into space on May 20. Controllers lost communication with LightSail twice during the flight, there were issues with the battery not operating correctly, and additional issues with the software were encountered during flight. On June 7, program managers on the ground once again established contact with the ornery vehicle. The sail was successfully deployed, but the first time controllers attempted to download an image from LightSail, it contained no usable data. Engineers downloaded the image again and worked until the full picture was visible.
"Then we got the big beautiful shot. We're feeling pretty good," Bill Nye, chief executive of the Planetary Society, said.
Despite the issues early in the flight, this first test flight of the crowdfunded spacecraft has achieved its major goal of unfurling its solar sail. The next mission, scheduled for 2016, will be launched to a greater altitude than this first flight, where it will be able to travel through space using the novel propulsion system.
"Next, engineers may 'walk out' the sail booms to increase the tension on the sails, which could further flatten the wavy appearance of the Mylar. The image also appears slightly distorted due to the camera's fish-eye lens. The team will analyze all sail imagery and any tensioning results in preparation for next year's flight, when LightSail operates in a higher orbit and uses sunlight for propulsion," Jason Davis of the Planetary Society wrote.
Carrying fuel is one of the greatest factors in the cost of space travel. Because solar sails use light as a propellant, these spacecrafts would provide a means of extremely low-cost travel among the inner planets.
A second image taken by LightSail may soon be downloaded to controllers. The vehicle was between the sun and our home planet when that image was taken, so it could include a new image of Earth as seen from space.
